Backlight unit and display device

ABSTRACT

A light generating device which may be used as a backlight unit and a display device including the light generating device are discussed. According to an embodiment, the light generating device can include a first layer; a plurality of light source devices disposed on the first layer and configured to emit light, each at least one of the light source devices including a light emitting unit diode for generating the light; a second layer covering the light source devices; and first and second light shielding layers disposed on the second layer and configure to selectively control transmit a propagation of the light emitted from the light source devices, the first and second light shielding layers being composed of a same material or different materials, the first and second light shielding layers being disposed to correspond with the light source devices.

This application claims the priority benefit of Korean PatentApplication No. 10-2010-0023387 filed on Mar. 16, 2010 and No.10-2010-0036926 filed on Apr. 21, 2010, and the priority benefit of U.S.Provisional Application No. 61/314,603 filed on Mar. 17, 2010, all ofwhich are incorporated herein by reference for all purposes as if fullyset forth herein.

BACKGROUND OF THE INVENTION

1. Field of the Invention

Exemplary embodiments of the invention relate to a backlight unit and adisplay device.

2. Description of the Related Art

In general, a typical large-sized display device includes a liquidcrystal display (LCD), a plasma display panel (PDP), and the like.Unlike the self-emission type PDP, the LCD needs a backlight unitbecause it generally does not have a light emitting device.

A backlight unit used in the LCD may be divided into an edge typebacklight unit and a direct type backlight unit depending on where lightsources are disposed. In the edge type backlight unit, light sources aredisposed at the left and right sides or upper and lower sides of an LCDpanel and a light guide plate is used to propagate the light emittedfrom the light sources, thereby obtaining light uniformity and allowingthe panel to become ultra-thin.

The direct type backlight unit is used for a 20 inch or larger display.In the direct type backlight unit, a plurality of light sources aredisposed under a panel and have superior light efficiency than the edgetype backlight unit. Thus, the direct type backlight unit is commonlyused for a large-scale display.

Conventional edge type backlight units or direct type backlight unitsemploy cold cathode fluorescent lamps (CCFLs) as light sources.

However, the backlight unit employing CCFLs is disadvantageous because,since power is constantly applied to the CCFLs, a great deal of power isconsumed, a color reproduction range (i.e., gamut) is about 70% of thatof a CRT, and the addition of mercury causes an environmental pollution.Thus, in an effort to address the problems, currently, research for abacklight unit employing light emitting diodes (LEDs) as a substitute isactively ongoing.

The use of the LEDs for a backlight unit allows for turning on and off aportion of an LED array and can remarkably reduce power consumption. Inthe case of an RGB LED, a 100% or more of a color reproduction range ofan NTSC (National Television System Committee) can be obtained toprovide more vivid picture quality. In addition, the LEDs manufacturedthrough a semiconductor process are less harmful to the environment.

Some LCD products employing the LEDs as a backlight unit having theforegoing advantages have been launched, but because their drivingmechanisms are different from that of the existing CCFL light source,the driver, PCB, and the like for such products are expensive and maynot be cost effective. Thus, conventionally the LED backlight unit isemployed only for high-priced LCD products.

SUMMARY OF THE INVENTION

Exemplary embodiments of the invention provide a backlight unit and adisplay device.

Embodiments of the invention provide a light generating device includingone or more light source devices each including a light emitting unitsuch as an LED, which can be used in a backlight unit or other deviceand which address the limitations and disadvantages associated with thebackground art.

According to an embodiment, the invention provides a light generatingdevice comprising: a first layer; a plurality of light source devicesdisposed on the first layer and configured to emit light, at least oneof the light source devices including a light emitting diode forgenerating the light; a second layer covering the light source devices;and first and second light shielding layers disposed on the second layerand configure to selectively transmit the light emitted from the lightsource devices, the first and second light shielding layers beingcomposed of different materials, the first and second light shieldinglayers being disposed to correspond with the light source devices.

According to an embodiment, the invention provides a light generatingdevice comprising: a first layer; a plurality of light source devicesdisposed on the first layer and configured to emit light, at least oneof the light source devices including a light emitting diode forgenerating the light; a second layer covering the light source devices;and a light shielding layer disposed on the second layer and configureto selectively transmit the light emitted from the light source devices,the light shielding layer including a plurality of holes, wherein widthsof the holes of the light shielding layer increase in a light emissiondirection.

According to an embodiment, the invention provides a light generatingdevice comprising: a first layer; a plurality of light source devicesdisposed on the first layer and configured to emit light, at least oneof the light source devices including a light emitting diode forgenerating the light; a second layer covering the light source devices;and a light shielding layer disposed on the second layer and configureto selectively transmit the light emitted from the light source devices,the light shielding layer including a plurality of through holes.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are included to provide a furtherunderstanding of the invention and are incorporated in and constitute apart of this specification, illustrate embodiments of the invention andtogether with the description serve to explain the principles of theinvention. In the drawings:

FIGS. 1A and 1B illustrate examples of a backlight unit according to anexemplary embodiment of the invention;

FIGS. 2A to 2C illustrate various examples of positions of a lightshielding layer according to an exemplary embodiment of the invention;

FIGS. 3A and 3B illustrate the distribution of a light transmittance ofthe light shielding layer according to an arrangement of light sourcesof the backlight unit according to an embodiment of the invention;

FIG. 4 is a graph showing an example of a light transmittance of thelight shielding layer according to the distance between adjacent lightsources according to an embodiment of the invention;

FIGS. 5A and 5B are respectively a plan view and a sectional viewshowing a light transmittance of a light shielding layer with aone-layered structure according to an embodiment of the invention;

FIGS. 6A and 6B are respectively a plan view and a sectional viewshowing a light transmittance of a light shielding layer with atwo-layered structure according to an embodiment of the invention;

FIGS. 7A and 7B are respectively a plan view and a sectional viewshowing a light transmittance of a light shielding layer with athree-layered structure according to an embodiment of the invention;

FIGS. 8A to 8E are sectional views showing an example of a backlightunit having a light shielding layer with a three-layered structureaccording to an embodiment of the invention;

FIG. 9 is a sectional view showing the sequential process of a methodfor manufacturing a backlight unit having the light shielding layer withthe three-layered structure according to an embodiment of the invention;

FIG. 10 is a view for explaining a light transmittance according to alight shielding pattern of a light shielding layer through a numericalexpression according to an embodiment of the invention;

FIGS. 11A and 11B illustrate examples of light shielding layers having alight shielding pattern according to an embodiment of the invention;

FIGS. 12A to 12C illustrate examples of a backlight unit having a lightshielding layer according to a first exemplary embodiment of theinvention;

FIGS. 13A and 13B illustrate examples of holes or recesses formed on thelight shielding layer according to the first exemplary embodiment of theinvention;

FIG. 14 illustrates a backlight unit having a light shielding layeraccording to a second exemplary embodiment of the invention;

FIGS. 15A and 15B illustrate examples of holes or recesses formed on thelight shielding layer according to the second exemplary embodiment ofthe invention;

FIGS. 16A to 16C illustrate a backlight unit having a light shieldinglayer according to a third exemplary embodiment of the invention;

FIGS. 17A to 17C illustrate a backlight unit having a light shieldinglayer according to a fourth exemplary embodiment of the invention;

FIGS. 18A to 18C illustrate a backlight unit having a light shieldinglayer according to a fifth exemplary embodiment of the invention;

FIGS. 19A and 19B illustrate examples of a backlight unit having a lightshielding layer according to a sixth exemplary embodiment of theinvention;

FIGS. 20A to 20C are sectional views showing sequential processes of amethod for manufacturing a light shielding layer according to the firstexemplary embodiment of the invention;

FIGS. 21A to 21C are sectional views showing sequential processes of amethod for manufacturing a light shielding layer according to the secondexemplary embodiment of the invention;

FIGS. 22A to 22C are sectional views showing sequential processes of amethod for manufacturing a light shielding layer according to the thirdexemplary embodiment of the invention;

FIG. 23 illustrates an example of a display module including a backlightunit according to an exemplary embodiment of the invention; and

FIGS. 24 and 25 illustrate examples of a display device including abacklight unit according to an exemplary embodiment of the invention.

DETAILED DESCRIPTION OF THE EMBODIMENTS

Reference will now be made in detail embodiments of the inventionexamples of which are illustrated in the accompanying drawings. In thisregard, each of all display devices, backlight units, light sourcedevices, and any device that includes such backlight unit or lightsource device discussed below is operatively coupled and configured.Further, a backlight unit according to embodiments of the invention canbe an edge type or a direct type as applicable. Furthermore, such abacklight unit preferably includes a plurality of light sources whichare disposed in arrays, lines, patterns, etc.

In these figures, arrows indicate a general light emitting direction ofthe light source, e.g., a general direction in which the light from alight emitting surface of the light source is emitted, but the lightfrom the light source may emit not necessarily in a single line butthrough an area in the indicated direction.

According to various embodiments of the invention, any one or morefeatures from one embodiment/example/variation of the invention can beapplied to (e.g., added, substituted, modified, etc.) any one or moreother embodiments/examples/variations discussed below according to theinvention. Further any operations/methods discussed below can beimplemented in any of these devices/units or other suitabledevices/units.

FIGS. 1A and 1B illustrate examples of a backlight unit according to anexemplary embodiment of the invention. Specifically, FIG. 1A illustratesa backlight unit having light sources 220 that emit light in lateraldirections, which may be used in an edge or direct type optical system,and FIG. 1B illustrates a backlight unit having light sources 220 thatemit light vertically, which may be used in an edge or direct typeoptical system.

As shown in FIGS. 1A and 1B, a backlight unit 200 may comprise a firstlayer 210, a light source 220, a second layer 230, a reflection layer240, and a light shielding layer 250.

Here, a plurality of light sources 220 are formed on the first layer210, and the second layer 230 is disposed at an upper side of the firstlayer 210 to cover the plurality of light sources 220. For instance, thesecond layer 230 encapsulates completely covers) the light sources 220disposed on the first layer 210.

The first layer 210 may be a board (or a substrate) on which theplurality of light sources 220 are mounted or formed, and an electrodepattern may be formed on the first layer 210 in order to connect anadapter for supplying power and the light sources 220. For example, acarbon nano-tube (CNT) electrode pattern for connecting the lightsources 220 and the adapter may be formed on the upper surface of thesubstrate.

The first layer 210 may be a PCB made of polyethylene terephthalate(PET), glass, polycarbonate (PC), silicon (Si), and the like, on whichthe plurality of light sources 220 are mounted or disposed. The firstlayer 210 may be formed in the form of a film.

The light sources 220 may be one of a light emitting diode (LED) chipand an LED package comprising at least one LED chip.

In the present exemplary embodiment, a case in which the light sources220 are an LED package will be described as an example.

The LED package constituting the light sources 220 may be classifiedinto a top view type LED package and a side view type LED packagedepending on the direction in which a light emitting surface points to.FIG. 1A illustrates the side view type LED package in which a lightemitting surface is formed to point toward a lateral side, and FIG. 1Billustrates the top view type LED package in which a light emittingsurface is formed to point toward an upper side.

The light sources according to an exemplary embodiment of the inventionmay be configured by using at least one of the side view type lightsources and the top view type light sources. For instance, in onebacklight unit, all side view type light sources may be used, all topview type light sources may be used, or a combination of the side andtop view type light sources may be used.

In an exemplary embodiment of the invention, in case of the LED packagehaving the side view type light sources 220, as shown in FIG. 1A, alight emitting surface of at least one of the plurality of light sources220 is disposed on the lateral side and the plurality of light sources220 may emit light to the lateral direction, namely, in the direction inwhich the first layer 210 or the reflection layer 240 extends.

In case of the LED package having the top view type light sources 220,as shown in FIG. 1B, a light emitting surface of at least one of theplurality of light sources 220 is disposed on the upper side and theplurality of light sources 220 may emit light to the upward direction,namely, in the direction of the second layer 230 and the light shieldinglayer 250.

The light sources 220 may be colored LEDs that emit at least one of red,blue, and green colors, or white LEDs. The colored LEDs may comprise atleast one of red LEDs, blue LEDs, and green LEDs. The disposition andemitted light of the LEDs may be variably modified so as to beapplicable.

The second layer 230 disposed on the first layer 210 and covering theplurality of light sources 220 may allow light emitted from the lightsources 220 to transmit therethrough and spread the light, whereby thelight emitted from the light sources 220 can be uniformly provided to adisplay panel 100, e.g., as shown in FIG. 23.

The reflection layer 240 for reflecting light emitted from the lightsources 220 may be positioned on the first layer 210. The reflectionlayer 240 may be formed on an area, of the first layer 210, other thanthe area where the light sources 220 are formed. For instance, thereflection layer 240 may completely surround the light sources 220 onthe first layer 210.

The reflection layer 240 may reflect light emitted from the lightsources 220 and reflect again the light (totally) reflected from theboundary of the second layer 230 to make the light to spread widely.

The reflection layer 240 may contain at least one of metal or a metaloxide, a reflective material. For example, the reflection layer 240 maybe made of metal or a metal oxide having a high reflectance such asaluminum (Al), silver (Ag), gold (Au) and titanium dioxide (TiO₂).

In this case, the reflection layer 240 may be formed by depositing orcoating the metal or metal oxide on the first layer 210 or by printingmetal ink on the first layer 210.

Here, a vacuum deposition method such as a thermal deposition method, anevaporation method, or a sputtering method may be used as the depositionmethod, and a printing method, a gravure coating method, or a silkscreen method may be used as the coating or printing method.

The second layer 230 positioned on the first layer 210 may be made of alight-transmissive material, e.g., silicon or an acrylic resin. However,the second layer 230 is not limited thereto and may be made of variousother resins.

In order to allow the backlight unit 200 to have a uniform luminancewhen light emitted from the light sources 220 spreads, the second layer230 may be made of a resin having a refractive index of about 1.4 to1.6. For example, the second layer 230 may be made of a materialselected from among the group consisting of polyethylene terephthalate(PET), polycarbonate (PC), polypropylene (PP), polyethylene (PE),polystyrene (PS), polyepoxy (PE), silicon, acryl, and the like.

The second layer 230 may comprise a polymer resin having an adhesiveproperty so as to be firmly and tightly attached to the light sources220 and the reflection layer 240. For example, the second layer 230 maybe made of acryl group, urethane group, epoxy group, and melamine groupsuch as unsaturated polyester, methyl methacrylate, ethyl methacrylate,isobutyl, methacrylate, n-butyl methacrylate, n-butyl methylmethacrylate, acrylic acid, methacrylic acid, hydroxyl ethylmethacylate, hydroxyl propyl methacrylate, hydroxyl ethyl acrylate,acrylamide, methylol acrylamide, glycidyl methacrylate, ethyl acrylate,isobutyl acrylate, n-butyl acrylate, 2-ethyl hexyl acrylate polymer,copolymer, or terpolymer.

The second layer 230 may be formed by coating a liquid or gel phaseresin on the first layer 210 with the plurality of light sources 220 andthe reflection layer 240 formed thereon and then hardening the resin.Alternatively, the second layer 230 may be formed by coating a resin ona support sheet, partially hardening it, and then bonding the same onthe first layer 210.

The second layer 230 may serve as a light guide plate for guiding thelight generated from the light sources 220. Subsequently, the lightshielding layer 250 reduces the luminance of light emitted from an areaadjacent to the light sources 220, thus serving to allow the light ofuniform luminance to be emitted from the backlight unit 200 to thedisplay panel of a display device. That is, the light shielding layer inthis embodiment or other embodiments discussed in the presentspecification can entirely reflect the light so that the light isblocked by the light shielding layer, or can partially transmit lightwhile partially reflecting the light.

Recently, as the backlight unit 200 tends to become thinner, and in thiscase, the reduction in the thickness of the backlight unit 200 can leadto degradation of light uniformity, To address this, the light shieldinglayer 250 is provided.

In the backlight unit 200, the area adjacent to the light emittingsurface of the light sources 220 is the brightest, while an area distantfrom the light emitting surface of the light sources 220 is less bright.Thus, the light shielding layer 250 may be manufactured such that itslight transmittance increases as it becomes away from the light emittingsurface of the light sources 220.

Namely, the light shielding layer 250 does not have the same lighttransmittance at its entire area but may have a different lighttransmittance at each area. For example, the area near the lightemitting surface of the light sources 220 has a low light transmittancewhile the area distant from the light emitting surface of the lightsources 220 has a high light transmittance

Also, the characteristics of a transmittance spectrum of the materialused for the light shielding layer 250 may not be uniform intransmitting light colored, which may degrade a color uniformity. Inthis case, however, if the light transmittance of the light shieldinglayer is adjusted to be increased in order to minimize a color change ofthe transmitted light, another problem may arise in that the lightshielding capability is likely to deteriorate. Thus, in an exemplaryembodiment of the invention, in manufacturing the light shielding layer250, an appropriate light shielding pattern may be additionally formedin consideration of these limitations.

The light shielding layer 250 according to an exemplary embodiment ofthe invention may be formed as a single layer whose respective areashave a different light transmittance, or may be formed as a plurality oflayers.

Also, the light shielding layer 250 may have a light shielding patterncomprising at least one of a plurality of holes and a plurality ofrecesses. Here, as for at least one of the holes and recesses, thedistance between the adjacent holes, the distance between the adjacentrecesses, or the distance between the adjacent hole and recess may bereduced as those become away from the light emitting surface of thelight sources 220.

The width of the light shielding pattern of the light shielding layer250 may be equal or may be gradually reduced as it becomes away from thelight emitting surface of the light sources 220.

The thickness of the light shielding layer 250 may be equal or may begradually reduced as it becomes away from the light emitting surface ofthe light sources 220. The light shielding layer 250 may be made of atleast one of a metal, TiO₂, CaCO₃, and ZnO.

FIGS. 2A to 3C illustrate various examples of positions of a lightshielding layer in a backlight unit according to an exemplary embodimentof the invention.

The light shielding layer 250 may be formed such that it is directlysupported on the second layer 230 made of a light-transmissive materialor in contact with the upper surface of the second layer 230 as shown inFIGS. 1A and 1B, or may be formed under a diffusion layer 260.

For instance, the diffusion layer 260 may be formed on the lightshielding layer 250 to allow light to spread upward, and in this case,the diffusion layer 260 may be directly bonded to the light shieldinglayer 250 or may be bonded by using an adhesive member.

Here, the diffusion layer 260 may serve to spread incident light bypreventing light, which comes from the light shielding layer 250, frombeing partially concentrated, thus making the light luminance moreuniform.

As shown in FIG. 2B, the light shielding layer 250 may be separated fromthe second layer 230 made of a light-transmissive material, by having acertain space 270 filled with air or gas interposed therebetween, and asshow in FIG. 2C, a buffer layer 280 may be additionally formed betweenthe light shielding layer 250 and the second layer 230.

Here, the buffer layer 280 may be the diffusion layer 260 in FIG. 2A, ormay be made of a material having a different refractive index from thatof the second layer 230. Also, the buffer layer 180 may be an adhesivefor improving an adhesive strength between the light shielding layer 250and the second layer 230 or may be a heat absorption layer remainingwhen the light shielding pattern of the light shielding layer 250 ismanufactured.

FIGS. 3A and 3B illustrate the distribution of a light transmittance ofthe light shielding layer according to an arrangement of light sourcesof the backlight unit. Specifically. FIG. 3A illustrates an arrangementstructure of light sources of the backlight unit, and FIG. 3Billustrates the distribution of a light transmittance of the lightshielding layer formed at the upper portion of the light sources of FIG.3A.

As shown in FIG. 3A, the plurality of light sources 220 are disposed onthe first layer 210. The adjacent light sources 220 may be arranged tobe parallel to each other on the same line or may be arranged in acrisscross manner.

Here, the light emitting surfaces of the light sources 220 may bedisposed to point toward the same direction. The light sources 220positioned on different, adjacent lines may be arranged to be parallelto each other or may be arranged in a crisscross manner.

Here, the light emitting surfaces of the light sources 220 positioned onthe same line may point toward the same direction, and the light sources220 positioned on the adjacent, different lines may be disposed suchthat their light emitting surfaces point toward the opposite direction.For instance, the light sources 220 arranged along a first line may emitlight in a first light emission direction, while the light sources 220arranged along a second line below the first line may emit light in asecond light emission direction which is different or opposite to thefirst light emission direction.

In an example, the distribution of a light transmission when the lightshielding layer 250 is formed at the upper side of the plurality ofarranged light sources 220 is shown in FIG. 3B.

As shown in FIG. 3B, assume that an area, nearest to the light emittingsurface of the light sources 220, of the upper surface area of the lightshielding layer 250 is a first area 300 a, an area farthest from thelight emitting surface of the light sources 220 is a third area 300 c,and an area positioned between the first area 300 a and the third area300 c is a second area 300 b. In this case, the first area 300 a has thelowest light transmittance, the third area 300 c has the highest lighttransmittance, and the second area 300 b has a median lighttransmittance or another light transmittance between those of the firstarea 300 a and the third area 300 c.

For instance, because the light transmittance of the area nearest to thelight emitting surface of the light sources 220 is lowest and the lighttransmittance of the area farthest from the light emitting surface ofthe light sources 220 is the highest, the quantity of light can beadjusted to have the uniform light transmittance degree overall.

FIG. 4 is a graph showing a light transmittance of the light shieldinglayer of the backlight unit according to the distance between adjacentlight sources. As shown in FIG. 4, it is noted that as one moves awayfrom the light emitting surface of the light source 220, the lighttransmittance of the light shielding layer is gradually increased.Namely, in an exemplary embodiment of the invention, the light shieldinglayer may be manufactured to have such a light transmittance as shown inFIG. 4.

Here, the light transmittance of the light shielding layer may beadjusted based on an equation shown below:

Light transmittance T(x)=10*e−a(L−x)n

In the above equation, 10 is the strength of the light sources. ‘L’ isthe interval between the adjacent light sources 220, ‘x’ is the distancebetween the light emitting surface of the light sources and a lighttransmittance measurement area, and ‘a’ and ‘n’ are coefficients.

In this manner, the areas of the light shielding layer between theadjacent light sources have different light transmittances, and thedifferent light transmittances may also vary depending on opticaldesigning conditions such as the number of light sources, a referencebrightness of the light sources, and the intervals between the lightsources.

Thus, in an exemplary embodiment of the invention, different lighttransmittances are set for the areas of the light shielding layer basedon the equation of the light transmittance T(x)=10*e−a(L−x)n, and thelight shielding layer may be manufactured according to the set lighttransmittances.

Namely, in manufacturing the light shielding layer, the order of settingthe light transmittances of the light shielding layer is as follows.

First, the optical designing conditions such as the number of lightsources, a reference brightness of the light sources, the intervalsbetween the light sources, and the like, are measured.

Next, light transmittances of the respective areas of the lightshielding layer are determined by using the equation T(x)=10*e−a(L−x)n.

And then, the light shielding layer is manufactured in consideration ofthe thickness of the light shielding layer, the material of the lightshielding layer, and the shape of a light shielding pattern of the lightshielding layer according to the determined light transmittances.

FIGS. 5A to 7B illustrate the light transmittances according to thethicknesses of the light shielding layer according to an embodiment ofthe invention. FIGS. 5A and 5B are respectively a plan view and asectional view showing a light transmittance of a light shielding layerwith a one-layered structure, FIGS. 6A and 6B are respectively a planview and a sectional view showing a light transmittance of a lightshielding layer with a two-layered structure, and FIGS. 7A and 7B arerespectively a plan view and a sectional view showing a lighttransmittance of a light shielding layer with a three-layered structure.

As shown in FIGS. 5A and 5B, the area, of a light shielding layer 250 aforming a one-layered structure, nearest to the light sources 220 hasthe highest light transmittance. As shown in FIGS. 6A and 6B, as thethickness of light shielding layers 250 a and 250 b forming atwo-layered structure increases, the light transmittance of the samearea is somewhat lowered. As shown in FIGS. 7A and 7B, the lighttransmittance at the same area of light shielding layers 250 a, 250 b,and 250 c forming a three-layered structure is even lower.

Thus, because the light transmittance varies according to the thicknessof the light shielding layer, a light shielding pattern may be formed byadjusting the thickness of the light shielding layer in order to obtainan effective distribution of light transmittance.

Among the light shielding layer, the area near the light sources needs alower light transmittance and a color change rate of transmitted lightmust be minimized at the area, while the area away from the lightsources needs a relatively high light transmittance. In order toimplement a light shielding layer having such a light transmittancedistribution, the adjustment of the thickness of the light shieldinglayer, as well as the light shielding pattern of a certain shape, is akey factor.

Thus, in manufacturing the light shielding layer according to anexemplary embodiment of the invention, its light transmittance can beadjusted by using the thickness of the light shielding layer as well asthe form of the light shielding pattern.

FIGS. 8A to 8E are sectional views showing an example of a backlightunit having a light shielding layer with a three-layered structureaccording to an embodiment of the invention.

As shown in FIG. 8A, a plurality of light shielding layers 250 may bepositioned on the second layer 230 of the backlight unit 200 comprisingthe light sources 220.

In more detail, the plurality of light shielding layers 250 may beformed on the second layer 230 such that they correspond to thepositions where the light sources 220 are disposed.

The light shielding layers 250 may comprise a first light shieldinglayer 250 a, a second light shielding layer 250 b, and a third lightshielding layer 250 c.

For example, the light shielding layers 250 may be formed on the secondlayer 230 such that the first light shielding layer 250 a is positionedto be in contact with the second layer 230, the second light shieldinglayer 2506 is positioned on (or in contact with) the first lightshielding layer 250 a, and the third light shielding layer 250 c ispositioned on (or in contact with) the second light shielding layer 250b.

The first light shielding layer 250 a and the third light shieldinglayer 250 c may be light shielding layers for shielding at least aportion of the light emitted from the light sources 220. The secondlight shielding layer 250 b may be a reflection layer for reflecting atleast a portion of the light emitted from the light sources 220.

Because the light shielding layers 250 are formed on the second layer230, the luminance of light emitted from an area adjacent to the lightsources 220 may be reduced, and accordingly, light of uniform luminancecan be emitted from the backlight unit 200.

For example, the light shielding layers 250 are formed on the secondlayer 230 such that they correspond to the positions where the pluralityof light sources 220 are disposed, to selectively shield or reflectlight emitted upward from the light sources 220 to reduce the luminanceof light emitted from the area adjacent to the light sources 220. And inthis case, the reflected light may spread to the lateral side or in adownward direction. For instance, a middle of the light shieldinglayer(s) 250 is selectively positioned to be aligned with orsubstantially aligned with a middle of the light sources 220, or thelight shielding layer(s) 250 are selectively positioned to generallycorrespond with the light sources 220.

The foregoing light shielding layers 250 may be formed by depositing orcoating a metal oxide. Alternatively, the light shielding layers 250 maybe formed by printing ink containing metal oxide, e.g., metal oxide ink,according to a predetermined pattern. In particular, the metal oxide inkmay be whitish ink.

Here, in order to improve the light shielding effect of the first andthird light shielding layers 250 a and 250 c, the first and third lightshielding layers 250 a and 250 c may have a color with a highbrightness, for example, a color close to white.

In this manner, the light shielding layer(s) 250 according to anexemplary embodiment of the invention serve to shield or reflect lightemitted from the light sources 220, to make the luminance of thebacklight unit uniform.

FIG. 8B illustrates examples of the path of light emitted from the lightsources 220.

As shown in FIG. 8B, light {circle around (1)} emitted in a directionhorizontal to the first layer 210, namely, in an x-axis direction, fromthe light source 220 may proceed toward the adjacent light source 220and be reelected by the adjacent light source 220. Light {circle around(2)} emitted in the direction of the reflection layer 240 from the lightsource 220 may be reflected from the reflection layer 240 and thenreflected from the first light shielding layer 250 a to proceed to theinterior of the second layer 230.

Also, light {circle around (3)} emitted in an upward direction from thelight source 220 may transmit through the second layer 230 so as to bereflected from the second light shielding layer 250 h to proceed upward.Light {circle around (4)} emitted in an upward direction from the lightsource 220 may be reflected from the first light shielding layer 250 adisposed on the light source 220, from which the light has been emitted,to proceed toward the reflection layer 240 and then reflected again fromthe reflection layer 240 so as to proceed outwardly.

Light {circle around (5)} emitted in the upward direction from the lightsource 220 may transmit through the first light shielding layer 250 adisposed on the light source 220 and be reflected from the second lightshielding layer 250 b so as to proceed outwardly.

Namely, the light shielding layers 250 may reflect light made incidentfrom the first to third light shielding layers 250 a to 250 c or mayreflect a portion of incident light and allow a portion of the incidentlight to transmit therethrough. The characteristics of the lightshielding layers 250 may be adjusted by controlling the transmission oflight through the second layer 230.

Accordingly, light emitted from the light source 220 can be widelyreflected in the lateral direction and other directions so as to spread,rather than being concentrated to the upper side, and thus, uniformluminance can be achieved by using the backlight unit.

As shown in FIG. 8A, the first, second, and third light shielding layers250 a, 250 b, and 250 c of the light shielding layers 250 may have thesame size and/or shape. Here, the size refers to the area on the planeof the first light shielding layer 250 a, the second light shieldinglayer 250 b, and the third light shielding layer 250 c. In an example,the first, second, and third light shielding layers 250 a, 250 b, and250 c having the same size and shape are sequentially stacked on thesecond layer 230.

Meanwhile, the foregoing light shielding layers 250 may be positionedsuch that their center corresponds to the center of the light sources220. The light shielding layers 250 may be formed to entirely cover thelight sources 220 positioned at the lower side of the light shieldinglayers 250.

Light emitted from the light source 220 has the highest luminance at alight emitting surface 221 of the light source 220, so the lightshielding layer 250 is positioned on the light emitting surface 221 ofthe light source 220 to reduce the luminance at the light emittingsurface 221 of the light source 220. In addition, because each lightsource 220 emits light toward the adjacent light source 220, lightreaching a rear surface 222 of the light source 220 is reflected fromthe light source or the reflection layer 240 adjacent to the lightsource 220, thus preventing an increase in the luminance at the rearsurface 222 of the light source 220.

Thus, the light shielding layer 250 may be positioned to entirely coverthe light emitting surface 221 and the rear surface 222 of the lightsource 220. Alternatively, the light shielding layer 250 may bepositioned to be lopsided toward the direction in which light is emittedfrom the light source 220 in order to reduce the luminance at the lightemitting surface 221 of the light source 220.

As shown in FIG. 8C, the light shielding layer 250 may be positionedsuch that the center of the light shielding layer 250 is consistent with(or aligned with) an extending line (L) of the light emitting surface221 of the light source 220. Namely, compared with the light shieldinglayer 250 illustrated in FIG. 8A; the light shielding layer 250illustrated in FIG. 8C is positioned to be off-centered more toward thelight emitting surface 221 of the light source 220.

As shown in FIG. 8D, the light shielding layer 250 may be positionedsuch that the center of the light shielding layer 250 shifted a certaindistance from the extending line (L) of the light emitting surface ofthe light source 220 in the direction in which light is emitted from thelight source 220. Namely, the light shielding layer illustrated in FIG.8D is more, off-centered toward the direction in which light is emittedfrom the light source 220 (light emitting direction) than the lightshielding layer illustrated in FIG. 8C.

As shown in FIG. 8E, the light shielding layer 250 may be positionedsuch that the end of the light shielding layer 250 is consistent with(or aligned with 0 the extending line (L) of the light emitting surface221 of the light source. Namely, the light shielding layer illustratedin FIG. 8E is even more off-centered toward the direction in which lightis emitted from the light source 220 than the light shielding layerillustrated in FIG. 8D.

Accordingly, the light shielding layer 250 can reduced the luminance atthe area adjacent to the light emitting surface 221 of the light source220, thus improving the uniformity of luminance of the backlight unit.

The foregoing light shielding layer having the three-layered structuremay be formed on a transparent film so as to be provided in thebacklight unit.

FIG. 9 is a sectional view showing the sequential process of a methodfor manufacturing a backlight unit having a light shielding layer with athree-layered structure according to an embodiment of the invention.

The method for manufacturing the light shielding layer 250 will now bedescribed as shown in FIG. 9. As shown in FIG. 9( a), the third lightshielding layer 250 c is formed on a transparent film 270 through adeposition, printing or coating method, the second light shielding layer250 b smaller than the third light shielding layer 250 c is formed onthe third light shielding layer 250 c, and the first light shieldinglayer 250 a is formed on the second light shielding layer 250 b suchthat it encapsulates the second light shielding layer 250 b. Forinstance, the second light shielding layer 250 b is encapsulated by thefirst and third light shielding layers 250 a and 250 c.

As shown in FIG. 9( b), the light sources 220 and the light shieldinglayers 250 are aligned such that they correspond to each other at theirpositions, and the transparent film 270 with the light shielding layers250 formed thereon is attached to the second layer 230, to form abacklight unit as shown in FIG. 9( c). Here, the light sources 220 andthe light shielding layers 250 may correspond with each other as shownin FIGS. 8A-8E.

The backlight unit formed as discussed above comprises the first lightshielding layer 250 a formed on the second layer 230 and the secondlight shielding layer 250 b covered by the third light shielding layer250 c. The third light shielding layer 250 c may be positioned on thesecond light shielding layer 250 b and the first light shielding layer250 a. The transparent film 270 may remain or may be removed later.

As shown in FIG. 9( c), certain edges of the first light shielding layer250 a are not in contact with the second layer 230, while other portionsof the first light shielding layer 250 a are in contact with the secondlayer 230 according to the degree of pressure applied to the transparentfilm 270. Further, in this example, a middle of the light shieldinglayer 250 may be aligned with or substantially aligned with a lightemitting surface 221 of the corresponding light source 220.

The respective layers (e.g., two or more layers) constituting the lightshielding layer may be made of different materials, or may be made ofthe same material.

FIG. 10 is a view for explaining a light transmittance according to alight shielding pattern of a light shielding layer in a backlight unitthrough a numerical expression according to an embodiment of theinvention. As shown in FIG. 10, when the area between the two adjacentlight sources 220 is divided into 10 sections, each section may comprisea light shielding pattern having a certain shape according to adetermined light transmittance.

When one of the 10 sections is a pattern cell, the pattern cell may havethe area called ‘A’. The pattern cell having the area ‘A’ may be an openarea (Aopen) with a hole formed therein or a patterned area (Apatterned)having a light shielding pattern.

Thus, if the pattern cell having the area ‘A’ does not include a lightshielding pattern, a light transmittance of the corresponding area isT(x)=open area of ‘A’ (Aopen)/entire area of ‘A’ (Acell).

The pattern cell having the area ‘A’ may comprise both an open area(Aopen) without a light shielding pattern and a patterned area(Apatterned) with a light shielding pattern. Here, the patterned area(Apatterned) with a light shielding pattern may be positioned at acentral portion or at an edge of the area ‘A’.

When a pattern transmittance of the patterned area (Apatterned) with alight shielding pattern is Tpattern, a light transmittance of thepattern cell having the area ‘A’ with a light shielding pattern isT(x)=open area (Aopen) of ‘A’/entire area (Acell) of ‘A’+{patterned area(Aclosed) of ‘A’*pattern transmittance (Tpattern)/entire area (Ault) of‘A’}.

Thus, when the light shielding pattern is formed on the light shieldinglayer, the light transmittance can be adjusted by using the equation asmentioned above.

Namely, when the light shielding pattern of the light shielding layer ismanufactured, the light transmittance of the light shielding layer canbe set in the order as follows.

First, because the light transmittance of each area of the lightshielding layer is previously set, the light transmittance of the areawhere the light shielding pattern is to be formed is searched to beconfirmed.

Next, the pattern area and open area of the corresponding area aredetermined by using the equation according to the pre-set lighttransmittance.

And then, a light shielding pattern is formed on the light shieldinglayer according to the determined pattern area and open area.

In this manner, in an exemplary embodiment of the invention, variouslight transmittances of the light shielding layer are determinedaccording to the designing conditions of the backlight such as lightsources, and the light shielding pattern of the light shielding layer isformed, thus manufacturing a backlight unit having the light shieldingpattern that can adjust the brightness of light to be uniform andminimize a color change of transmitted light.

FIGS. 11A and 11B illustrate examples of light shielding layers having alight shielding pattern for use in a backlight unit according to anembodiment of the invention. Specifically, FIG. 11A illustrates a lightshielding layer having a three-layered structure with a light shieldingpattern in the form of holes, and FIG. 11B illustrates a light shieldinglayer having a one-layered structure with a light shielding pattern inthe form of grooves. Such light shielding layers each can be disposed inthe backlight unit in any manner discussed above.

As shown in FIG. 11A, the light shielding layer having a light shieldingpattern in the form of holes may have the structure in which the firstlight shielding layer 250 a, the second light shielding layer 250 b, andthe third light shielding layer 250 c are stacked, but the lightshielding layer may have a two-layered structure in which the firstlight shielding layer 250 a and the second light shielding layer 250 bare stacked, or may be formed as a single layer comprising only thefirst light shielding layer 250 a according to circumstances.

In light shielding layer having the three-layered structure, the firstlight shielding layer 250 a comprises a first area without a first lightshielding pattern and a second area adjacent to an outer boundary of thefirst area and having the first light shielding pattern.

The second light shielding layer 250 b may be formed on the first areaof the first light shielding layer 250 a and may comprise a third areawithout a second light shielding pattern and a fourth area adjacent tothe outer boundary of the third area and having the second lightshielding pattern.

The third light shielding layer 250 c may be formed on the third area ofthe second layer 250 h and comprise a fifth area with a third lightshielding pattern.

Here, the light source may be positioned to correspond to the fifth areaof the third light shielding layer 250 c. The light shielding layernearest to the light source may have the three-layered structure, whichis the thickest, and the light shielding layer farthest from the lightsource may have a one-layered structure, which is the thinnest.

FIG. 11B illustrates the light shielding layer having the one-storiedstructure with a light shielding pattern in the form of recesses. Asshown in FIG. 11B, the light shielding layer is configured as a singlelayer and may be formed such that its thickness is gradually reduced asthe light shielding layer extends away from the light source, e.g., thethickness of the light shielding layer may decrease as the lightshielding layer extends in the light emitting direction of the lightsource.

The light shielding pattern of the light shielding layer illustrated inFIG. 11B can be formed by using a mold 800 having a certain pattern.Namely, the pattern of the mold 800 can be transferred to the lightshielding layer 250 to form the light shielding pattern.

In this case, the area near the light source may be thicker and have arecess-like light shielding pattern, while the area away from the lightsource may be thinner and have a recess or hole-like light shieldingpattern. The recess-like light shielding pattern may have a surface withmultiple indents, while the hole-like light shielding pattern mayinclude through-holes within the pattern.

FIGS. 12A to 12C illustrate examples of a backlight unit having a lightshielding layer according to a first exemplary embodiment of theinvention. Specifically. FIG. 12A illustrates a light shielding layerhaving a single-layered structure with a light shielding pattern havinga varying thickness, FIG. 12B illustrates a light shielding layer havinga multi-layered structure with a light shielding pattern having avarying thickness, and FIG. 12C illustrates a backlight unit employingthe light shielding layer with a different light shielding patternhaving a different thickness. These light shielding layers allow a moreuniform light emission from the entire area of the backlight unit.

As shown in FIG. 12A, the light shielding layer 250 having asingle-layered structure may be manufactured such that respective areashave different thicknesses according to their light transmittance.

For instance, among the entire area of the light shielding layer 250, anarea through which the brightest light transmits may have the largestthickness d1 corresponding to a pertinent light transmittance so as toshield the largest amount of light, and an area through which the leastamount of light transmits may have the smallest thickness d3corresponding to a pertinent light transmittance so as to shield thesmallest amount of light.

As shown in FIG. 12B, the light shielding layer 250 having amulti-layered structure comprising multiple layers may be manufacturedsuch that one layer or multiple layers are stacked, which provides thelight shielding layer 250 having a varying thickness according to alight transmittance of each area.

Namely, among the entire area of the light shielding layer 250, thefirst, second, and third light shielding layers 250 a, 250 b, and 250 cmay be stacked to have a varying thickness corresponding to a pertinentlight transmittance at an area through which the brightest light maytransmit so as to shield a largest amount of light, and only the firstlight shielding layer 250 a may be formed to have the thicknesscorresponding to a pertinent light transmittance at an area throughwhich the least amount of light may transmit so as to shield thesmallest amount of light. For instance, the portion of the lightshielding layer 250 having the thickness d1 may be disposed tocorrespond with the corresponding light source 220.

The multi-layered structure of FIG. 12B may be advantageous in that eachlayer may be made of a different material and the light shielding layer250 may have a different total thickness, so the light transmittance canbe more finely adjusted compared with the single-layered structure. Forinstance, the portion of the light shielding layer 250 having thelargest total thickness (e.g., where the layers 250 a-250 c are formed)may be disposed to correspond with the corresponding light source 220.

As shown in FIG. 12C, the light shielding layer 250 at the area nearestto the light source 220 is thicker, and the light shielding layer 250 atthe area away from the light source 220 is thinner, thus uniformlyadjusting the light transmittance.

In the first exemplary embodiment of the invention, an open area such asa hole or a recess may be formed on the light shielding layer 250according to circumstances.

Here, the width of the open area may gradually increase or may be equalas the light shielding layer extends away from the light source.

FIGS. 13A and 13B illustrate holes or recesses formed on the lightshielding layer according to the first exemplary embodiment of theinvention. As shown in FIGS. 13A and 13B, the depth of the hole orrecess formed on the third light shielding layer 250 c may be equal to athickness value of the third light shielding layer 250 c, may be equalto a thickness value obtained by adding the thicknesses of the secondand third light shielding layers 250 b and 250 c, or may be equal to athickness value obtained by adding the thicknesses of the first, second,and third light shielding layers 250 a, 250 b, and 250 c.

The depth of the hole or recess formed on the second light shieldinglayer 250 b may be equal to the thickness value of the second lightshielding layer 250 b or may be equal to a thickness value obtained byadding the thicknesses of the first and second light shielding layers250 a and 250 b.

The depth of the hole or recess formed on the first light shieldinglayer 250 a may be equal to a thickness value of the first lightshielding layer 250 a or smaller. For instance, in the example of FIG.13A, all through holes are aligned and formed through the all therespective layers of the light shielding layer 250. In another exampleof FIG. 13B, through holes are formed only at a top layer of therespective layers of the light shielding layers 250. These through holesprovide patterns for providing a more uniform light transmission.

FIG. 14 illustrates a backlight unit having a light shielding layeraccording to a second exemplary embodiment of the invention. In FIG. 14,the light shielding pattern of the light shielding layer 250 has anisland-like shape.

As shown in FIG. 14, the light shielding layer 250 according to thesecond exemplary embodiment of the invention has such a form that thetilts at both sides are different. The light shielding layer at an areanearest to the light source 220 is thicker and has a tilt with a steepslope while the light shielding layer at an area distant from the lightsource 220 is thinner and has a tilt with a gentle slope, thus uniformlyadjusting the light transmittance.

In the second exemplary embodiment of the invention, an open area suchas a hole or a recess may be formed on the light shielding layer 250according to circumstances. Here, the width of the open area maygradually increase or may be equal as the light shielding layer 250extends away from the light source.

FIGS. 15A and 15B illustrate examples of holes or recesses formed on thelight shielding layer according to the second exemplary embodiment ofthe invention. As shown in FIGS. 15A and 15B, the depth of the holes orrecesses may vary depending on the thicknesses of the light shieldinglayer. Preferably, the portion of the light shielding layer that is thethickest may correspond with the respectively light source.

FIGS. 16A to 16C illustrate a backlight unit having a light shieldinglayer according to a third exemplary embodiment of the invention.Specifically, FIG. 16A illustrates a light shielding layer whose holewidth and light shielding pattern width vary, FIG. 16B illustrates aplan view of the light shielding layer of FIG. 16A, and FIG. 16Cillustrates a backlight unit employing the light shielding layer havingthe different hole widths and light shielding pattern widths.

In the third exemplary embodiment of the invention, as shown in FIGS.16A to 16C, the hole widths w1 and the light shielding pattern widths w2formed on the light shielding layer 250 vary as the light shieldinglayer 250 extends away from the light source 220.

Namely, the hole width w1 of the light shielding layer 250 graduallyincreases as the light shielding layer extends away from the lightsource 220, and at the same time the light shielding pattern width w2 ofthe light shielding layer 250 gradually decreases as the light shieldinglayer extends away from the light source 220. In an example, the portionof the light shielding layer 250 that has a larger width w2 would bepositioned to correspond with the light source 220 as shown in FIG. 16C.

In the third exemplary embodiment of the invention, the light shieldinglayer 250 may be a single layer or may be configured as a plurality oflayers comprising at least two or more layers, according tocircumstances.

FIGS. 17A to 17C illustrate a backlight unit having a light shieldinglayer according to a fourth exemplary embodiment of the invention.Specifically, FIG. 17A illustrates a light shielding layer whose lightshielding pattern width is uniform and hole width varies, FIG. 17B is aplan view of the light shielding layer of FIG. 17A, and FIG. 17Cillustrates a backlight unit employing the light shielding layer whoselight shielding pattern width is uniform and hole width varies.

In the fourth exemplary embodiment of the invention, as shown in FIGS.17A to 17C, the hole width w1 formed on the light shielding layer 250varies as the light shielding layer 250 extends away from the lightsource 220, while the light shielding pattern width w2 is uniform.

Namely, the hole width w1 of the light shielding layer 250 graduallyincreases as the light shielding layer 250 extends away from the lightsource 220, while the light shielding pattern width w2 of the lightshielding layer 250 is uniform although the light shielding layer 250extends away from the light source 220.

In the fourth exemplary embodiment of the invention, the light shieldinglayer 250 may be a single layer or may be configured as a plurality oflayers comprising at least two or more layers, according tocircumstances.

FIGS. 18A to 18C illustrate a backlight unit having a light shieldinglayer according to a fifth exemplary embodiment of the invention.Specifically, FIG. 18A illustrates a light shielding layer whose holewidth is uniform and light shielding pattern width varies, FIG. 18B is aplan view of the light shielding layer of FIG. 18A, and FIG. 18Cillustrates a backlight unit employing the light shielding layer whosehole width is uniform and light shielding pattern width varies.

In the fifth exemplary embodiment of the invention, as shown in FIGS.18A to 18C, the light shielding pattern width w2 formed on the lightshielding layer 250 varies as the light shielding layer 250 extends awayfrom the light source 220, while the hole width w1 is uniform.

Namely, the light shielding pattern width w2 of the light shieldinglayer 250 gradually decreases as the light shielding layer 250 extendsaway from the light source 220, while the hole width w1 of the lightshielding layer 250 is uniform although the light shielding layer 250extends away from the light source 220.

In the fifth exemplary embodiment of the invention, the light shieldinglayer 250 may be a single layer or may be configured as a plurality oflayers comprising at least two or more layers, according tocircumstances.

FIGS. 19A and 19B illustrate a backlight unit having a light shieldinglayer according to a sixth exemplary embodiment of the invention.Specifically, FIG. 19A illustrates the reflection characteristics oflight reflected from upper and lower portions of a light shieldinglayer, and FIG. 19B illustrates a backlight unit employing the lightshielding layer having different reflection characteristics of light atthe upper and lower portions thereof.

In the sixth exemplary embodiment of the invention, as shown in FIGS.19A and 19B, the light shielding layer may additionally comprise areflective film 400 formed on the light shielding layer 250. That is,the light shielding layer of the invention may include the reflectivefilm 400 and the light shielding layer discussed above.

Here, the reflective film 400 may be made of a material that candiffused-reflect incident light. For example, the reflective film 400may be formed as a white ink thin film or the like. Namely, the lightshielding layer 250 illustrated in FIG. 19A may be formed as a metalthin film layer having a high reflectance to specular-reflect anincident light, and the reflective film 400 formed on the lightshielding layer 250 may diffuse the reflected incident light.

As shown in FIG. 19B, when the light shielding layer 250 with thereflective film 400 formed thereon is applied to the backlight unit,light outputted from the light source 220 transmits through the hole orpattern of the light shielding layer 250, is reflected from the opticalsheet 500 positioned at the upper side, and is then made incident to thereflective film 400. Then the light made incident to the reflective film400 is diffused and/or reflected by the reflective film 400 so as to beuniformly diffused.

Accordingly, the light shielding layer 250 with the reflective film 400formed thereon renders a point source of light be a surface lightsource, which is somewhat advantageous compared with the light shieldinglayer 250 without the reflective film 400.

In this manner, the light shielding layers having various structures canbe manufactured in various manners according to the invention.

FIGS. 20A to 20C are sectional views showing sequential processes of amethod for manufacturing a light shielding layer according to the firstexemplary embodiment of the invention.

In the first exemplary embodiment of the invention, as shown in FIG.20A, first, the light shielding layer 250 is formed on a substrate 700,and a mask layer 600 is formed on the light shielding layer 250.

Here, the light shielding layer 250 may be a metal layer, and the masklayer 600 may be made of a material that does not react to an etchant ofthe light shielding layer 250. For example, when the light shieldinglayer 250 is made of a metal, the mask layer 600 may be white inkcomprising organic and inorganic particles.

Next, the mask layer 600 is patterned according to a light shieldingpattern desired to be formed to expose portions of the light shieldinglayer 250. Here, the light shielding patterns discussed above can beused.

And then, as shown in FIG. 20B, the exposed portions of the lightshielding layer 250 are etched to be removed by using the patterned masklayer 600 as a mask.

Thereafter, as shown in FIG. 20C, the remaining mask layer 600 isremoved to form the light shielding layer 250 having the light shieldingpattern.

The process of FIG. 20C may not be performed to leave the mask layer 600on the light shielding layer 250, rather than being removed, accordingto circumstances. A reason that this may be desired is because when themask layer 600 is formed as a reflective film such as white ink, themask layer 600 may be left as it is on the light shielding layer 250 toserve to diffuse-reflect the light made incident to the mask layer 600,in the similar manner as in the sixth exemplary embodiment of theinvention.

In this manner, the method for manufacturing the light shielding layeraccording to the first exemplary embodiment of the invention uses thechemical etching process combined with the photoresist process.

FIGS. 21A to 21C are sectional views showing sequential processes of amethod for manufacturing a light shielding layer according to the secondexemplary embodiment of the invention.

In the method for manufacturing a light shielding layer according to thesecond exemplary embodiment of the invention, patterning is performed byusing a pulse laser. A basic mechanism is that a light absorptionmaterial absorbs a pulse laser to cause an instantaneous thermalexpansion, and the light absorption material is then separated from thesubstrate due to such a rapid thermal expansion.

The process is a direct photoetching process that does not require thephotoresist process and the chemical etching process. In the directphotoetching process, sufficient interaction must be made between thelaser beam and the light absorption material and the phenomenon mustoccur within a short time.

In the second exemplary embodiment of the invention, first, as shown inFIG. 21A, the light shielding layer 250 and the mask layer 600 aresequentially formed on the substrate 700, and the mask layer 600 ispatterned according to a light shielding pattern desired to be formed,to expose portions of the light shielding layer 250.

Next, as shown in FIG. 21B, a pulse laser is irradiated to the oppositesurface of the light-transmissive substrate 700 with the light shieldinglayer 250 formed thereon. Here, the light shielding layer 250 is made ofa light absorption material that absorbs the laser beam, andaccordingly, the laser beam which has passed through thelight-transmissive substrate 700 is absorbed by the light shieldinglayer 250.

The light shielding layer 250 is instantly thermally expanded and, inthis case, the relatively thinner portions of the light shielding layer250, e.g., the portions exposed from the mask layer 600, are detachedfrom the substrate 700 as shown.

And then, as shown in FIG. 21C, the remaining mask layer 600 is removedto form the light shielding layer 250 having the light shieldingpattern. In a variation, the process of FIG. 21C may not be performedand the mask layer 600 may be maintained on the light shielding layer250 as it is, rather than being removed, according to circumstances. Areason for this may be because when the mask layer 600 is formed as areflective film such as white ink, the mask layer 600 may be maintainedas it is to serve to diffuse-reflect the light made incident to the masklayer 600, in the similar manner as in the sixth exemplary embodiment ofthe invention.

In this manner, the method for manufacturing the light shielding layeraccording to the second exemplary embodiment of the invention uses thephysical etching process combined with the photoresist process and thepulse laser patterning process.

FIGS. 22A to 22C are sectional views showing sequential processes of amethod for manufacturing a light shielding layer according to the thirdexemplary embodiment of the invention.

In the third exemplary embodiment of the invention, first, as shown inFIG. 22A, the light shielding layer 250 is formed on thelight-transmissive substrate 700, and the mask layer 600 is formed onthe opposite side of the light-transmissive substrate 700 on which thelight shielding layer 250 is formed.

Next, the mask layer 600 is patterned according to a light shieldingpattern desired to be formed to expose portions of the light shieldinglayer 250.

And then as shown in FIG. 22B, a pulse laser is irradiated to thelight-transmissive substrate 700 with the mask layer 600 formed thereonby using the mask layer 600 as a mask. Here, the light shielding layer250 is made of a light absorption material that absorbs the laser beam,and accordingly, the laser beam which has passed through thelight-transmissive substrate 700 is absorbed by the light shieldinglayer 250. The portions of the light shielding layer 250 which haveabsorbed the laser beam are instantly thermally expanded and thendetached from the substrate 700.

Thereafter, as shown in FIG. 22C, the remaining mask layer 600 isremoved to form the light shielding layer 250 having the light shieldingpattern.

The process of FIG. 22C may not be performed to leave the mask layer 600as it is, rather than being removed, according to circumstances.

In this manner, the method for manufacturing the light shielding layeraccording to the third exemplary embodiment of the invention uses thephysical etching process combined with the photoresist process and thepulse laser patterning process.

FIG. 23 illustrates a display module comprising a backlight unitaccording to an exemplary embodiment of the invention.

As shown in FIG. 23, a display module (e.g., a display module 20 asshown in FIG. 24) may comprise the display panel 100 and the backlightunit 200.

The display panel 100 comprises a color filter substrate 110 and a thinfilm transistor (TFT) substrate 120 attached in a facing manner with acell gap maintained therebetween, and a liquid crystal layer may beinterposed between the two substrates 110 and 120.

The color filter substrate 110 may comprise a plurality of color filterscomprising red (R), green (G), and blue (B) color filters, and generatean image corresponding to the red, green, and blue color when light isapplied thereto.

The color filters may comprise the red, green, and blue color filters,but without being limited thereto, red, green, blue, and white (W)subpixels may constitute a single pixel and thus different color filtersmay be used.

The TFT substrate 120 comprises switching elements (e.g., TFTs) toswitch pixel electrodes. For example, a common electrode and pixelelectrodes may vary the alignment of liquid crystal molecules of theliquid crystal layer according to a certain voltage applied from anexternal source.

The liquid crystal layer comprises a plurality of liquid crystalmolecules, and the alignment of the liquid crystal molecules may bechanged according to a voltage difference between the pixel electrodesand the common electrode. Accordingly, light provided from the backlightunit 200 may be made incident to the color filter substrate 110correspondingly according to the change in the alignment of the liquidcrystal molecules of the liquid crystal layer.

An upper polarizer 130 and a lower polarizer 140 may be disposed on theupper and lower sides of the display panel 100, respectively.Specifically, the upper polarizer 130 may be disposed on an uppersurface of the color filter substrate 110, and the lower polarizer 140may be disposed on a lower surface of the TFT substrate 120.

Although not shown, gate and data driving units may be provided to theside of the display panel 100 in order to generate driving signals fordriving the panel 100.

As shown in FIG. 23, the display module according to an exemplaryembodiment of the invention may be configured such that the backlightunit 200 is tightly attached to the display panel 100. For example, thebacklight unit 200 may be fixedly bonded to a lower side of the displaypanel 100, e.g., to the lower polarizer 140, for which an adhesive layermay be formed between the lower polarizer 140 and the backlight unit200.

Because the backlight unit 200 is tightly attached to the display panel100, the overall thickness of the display device can be reduced toimprove the external appearance of the display device, and because anadditional structure for fixing the backlight unit 200 may be omitted,the structure and manufacturing process of the display device can besimplified.

Also, because there is no space between the backlight unit 200 and thedisplay panel 100, malfunctions of the display device otherwise causedby an infiltrated debris into such a space or degradation of the picturequality of a display image can be prevented or reduced.

The backlight unit 200 according to an exemplary embodiment of theinvention may be configured by stacking a plurality of function layers,and at least one of the plurality of function layers may comprise aplurality of light sources. Various examples of the light sourcesdiscussed above can be used.

In addition, in order for the backlight unit 200 to be tightly attachedto be fixed to the lower surface of the display panel 100, the backlightunit 200, e.g., the plurality of function layers constituting thebacklight unit 200 may be made of a flexible material.

The display panel 100 according to an exemplary embodiment of theinvention may be divided into a plurality of areas, and the brightnessof light emitted from a corresponding area of the backlight unit 200,namely, the brightness of a corresponding light source, may be adjustedaccording to a gray peak value of each of the divided areas or a colorcoordinates signal, thus adjusting the luminance of the display panel100. To this end, the backlight unit 200 may be divided into a pluralityof division driving areas which correspond to the divided areas of thedisplay panel 100, respectively, so as to operate. For instance, thebacklight unit can be divided into regions which can be selectively andindependently driven, e.g., turned on/off, provide dimmed light, etc.

FIGS. 24 and 25 illustrate a display device according to an exemplaryembodiment of the invention. Here, the display module 20 includes anybacklight unit discussed above and a display panel to which the lightfrom the backlight unit is applied.

As shown in FIG. 24, a display device 1 according to an exemplaryembodiment of the invention may comprise a display module 20, a frontcover 30 and a back cover 35 that Covers the display module 20, adriving unit 55 provided on the back cover 35, and a driving unit cover40 that covers the driving unit 55.

The front cover 30 may comprise a front panel made of a transparentmaterial allowing light to transmit therethrough. The front panelprotects the display module 20 at a certain distance and allows lightemitted from the display module 20 to transmit therethrough so that animage displayed on the display module 20 can be seen from the outside.

The front cover 30 may be formed of a flat plate without a window 30 a.In this case, the front cover 30 may be made of a transparent materialallowing light to transmit therethrough. For example, the front cover 30may be made of injection-molded plastic. When the front cover 30 isformed of a flat plate, the front cover 30 does not need to have aframe.

The back cover 35 may be coupled with the front cover 30 to protect thedisplay module 20. The driving unit 55 may be disposed on one surface ofthe back cover 35. The driving unit 55 may comprise a driving controller55 a, a main board 55 b, and a power supply unit 55 c.

The driving controller 55 a, which may be a timing controller, controlsan operation timing of each driver 1C of the display module 20. The mainboard 55 b transfers V SYNC, H SYNC, R, G, and B resolution signals, andother signals to the timing controller. The power supply unit 55 capplies power to the display module 20. The driving unit 55 may beprovided on the back cover 35 and covered by the driving unit cover 40.

The back cover 35 comprises a plurality of holes to allow the displaymodule 20 and the driving unit 55 to be connected to each other. A stand60 may be provided to support the display device 1.

As shown in FIG. 24, the driving controller 55 a of the driving unit 55may be provided on the back cover 35, and the main hoard 55 b and thepower supply unit 55 c may be provided at the stand 60. The driving unitcover 40 may cover only the driving unit 55 formed at the back cover 35.

In the present exemplary embodiment, the main board 55 b and the powersupply unit 55 c are separately configured, but the invention is notmeant to be limited thereto and the main board 55 b and the power supplyunit 55 c may be configured as a single integrated board.

Although embodiments have been described with reference to a number ofillustrative embodiments thereof, it should be understood that numerousother modifications and embodiments can be devised by those skilled inthe art that will fall within the scope of the principles of thisdisclosure. More particularly, various variations and modifications arepossible in the component parts and/or arrangements of the subjectcombination arrangement within the scope of the disclosure, the drawingsand the appended claims. In addition to variations and modifications inthe component parts and/or arrangements, alternative uses will also beapparent to those skilled in the art.

1. A light generating device comprising: a first layer; a plurality oflight source devices disposed on the first layer and configured to emitlight, at least one of the light source devices including a lightemitting diode for generating the light; a second layer covering thelight source devices; and first and second light shielding layersdisposed on the second layer and configured to selectively transmit thelight emitted from the light source devices, the first and second lightshielding layers being composed of different materials, the first andsecond light shielding layers being disposed to correspond with thelight source devices.
 2. The light generating device of claim 1, furthercomprising: a third light shielding layer disposed on the second lightshielding layer and corresponding to the light source devices, whereinthe first and third light shielding layers are composed of a samematerial.
 3. The light generating device of claim 2, wherein widths ofthe first, second and third light shielding layers vary from each other.4. The light generating device of claim 3, wherein the widths oldiefirst, second and third light shielding layer decrease in a directionperpendicular to a light emission direction.
 5. The light generatingdevice of claim 1, wherein a total thickness of any light shieldinglayer disposed at areas corresponding to the light source devices isgreater than a total thickness of any light shielding layer disposed atareas adjacent to the areas corresponding to the light source devices.6. The light generating device of claim 1, wherein each of the first andsecond light shielding layers includes at least one through-hole.
 7. Thelight generating device of claim 6, wherein the through-holes of thefirst and second light shielding layers are aligned with each other. 8.The light generating device of claim 6, wherein widths of thethrough-holes of the first and second light shielding layers increase ina light emission direction.
 9. The light generating device of claim 2,wherein at least one of the first, second and third light shieldinglayers includes at least one through-hole.
 10. The light generatingdevice of claim 9, wherein each of the first, second and third lightshielding layers includes the at least one through-hole, and thethrough-holes of the first, second and third light shielding layers arealigned with each other.
 11. The light generating device of claim 9,wherein widths of the through-holes of the first, second and third lightshielding layers increase in a light emission direction.
 12. The lightgenerating device of claim 1, further comprising: a reflection layerdisposed on the first layer and configured to reflect the light emittedfrom the light source devices.
 13. The light generating device of claim1, wherein the plurality of light source devices are arranged inmultiple lines.
 14. A display device comprising: a display panelconfigured to display images; and a backlight unit including the lightgenerating device of claim 1 and configured to supply the light from thelight generating device to the display panel.
 15. The display device ofclaim 14, wherein the plurality of light source devices in the backlightunit extend in arrays and correspond to a display area of the displaypanel.
 16. A light generating device comprising: a first layer; aplurality of light source devices disposed on the first layer andconfigured to emit light, at least one of the light source devicesincluding a light emitting diode for generating the light; a secondlayer covering the light source devices; and a light shielding layerdisposed on the second layer and configured to selectively transmit thelight emitted from the light source devices, the light shielding layerincluding a plurality of holes, wherein widths of the holes of the lightshielding layer increase in a light emission direction.
 17. The lightgenerating device of claim 16, wherein a thickness of the lightshielding layer decreases in the light emission direction.
 18. A lightgenerating device comprising: a first layer; a plurality of light sourcedevices disposed on the first layer and configured to emit light, atleast one of the light source devices including a light emitting diodefor generating the light; a second layer covering the light sourcedevices; and a light shielding layer disposed on the second layer andconfigured to selectively transmit the light emitted from the lightsource devices, the light shielding layer including a plurality ofthrough holes.
 19. The light generating device of claim 18, whereinwidths of the through holes of the light shielding layer are uniform,and wherein widths between the through holes of the light shieldinglayer decrease in a light emission direction.
 20. A display devicecomprising: a display panel configured to display images; and abacklight unit including the light generating device of claim 18 andconfigured to supply the light from the light generating device to thedisplay panel.